John Bordley Rawls (/rɔːlz/; February 21, 1921 – November 24, 2002) was an American moral, legal and political philosopher in the modern liberal tradition. Rawls has been described as one of the most influential political philosophers of the 20th century.

In 1990, Will Kymlicka wrote in his introduction to the field that "it is generally accepted that the recent rebirth of normative political philosophy began with the publication of John Rawls's A Theory of Justice in 1971". Rawls's theory of "justice as fairness" recommends equal basic liberties, equality of opportunity, and facilitating the maximum benefit to the least advantaged members of society in any case where inequalities may occur. Rawls's argument for these principles of social justice uses a thought experiment called the "original position", in which people deliberately select what kind of society they would choose to live in if they did not know which social position they would personally occupy. In his later work Political Liberalism (1993), John Rawls addressed the question of how political power can be exercised legitimately in a society where citizens hold diverse and often conflicting moral, religious, and philosophical points of view.

Rawls received both the Schock Prize for Logic and Philosophy and the National Humanities Medal in 1999. The latter was presented by President Bill Clinton in recognition of how his works "revived the disciplines of political and ethical philosophy with his argument that a society in which the most fortunate help the least fortunate is not only a moral society but a logical one".

Among contemporary political philosophers, Rawls is frequently cited by the courts of law in the United States and Canada and referred to by practicing politicians in the United States and the United Kingdom. In a 2008 national survey of political theorists, based on 1,086 responses from professors at accredited, four-year colleges and universities in the United States, Rawls was voted first on the list of "Scholars Who Have Had the Greatest Impact on Political Theory in the Past 20 Years".

Rawls was born on February 21, 1921, in Baltimore, Maryland, the second of five sons. His father, William Lee Rawls, was a prominent Baltimore attorney, and his mother, Anna Abell Stump Rawls, was active in local Democratic politics, including advocacy for women’s voting rights. Tragedy struck Rawls at a young age:

Two of his brothers died in childhood because they had contracted fatal illnesses from him. ... In 1928, the seven-year-old Rawls contracted diphtheria. His brother Bobby, younger by 20 months, visited him in his room and was fatally infected. The next winter, Rawls contracted pneumonia. Another younger brother, Tommy, caught the illness from him and died.

Rawls's biographer Thomas Pogge calls the loss of the brothers the "most important events in John's childhood".

Rawls graduated in Baltimore before enrolling in the Kent School, an Episcopalian preparatory school in Connecticut. Upon graduation in 1939, Rawls attended Princeton University, where he was accepted into the Ivy Club and the American Whig–Cliosophic Society. At Princeton, Rawls was influenced by Norman Malcolm, Ludwig Wittgenstein's student. During his last two years at Princeton, he "became deeply concerned with theology and its doctrines". He considered attending a seminary to study for the Episcopal priesthood and wrote an "intensely religious senior thesis (BI)". In his 181-page long thesis titled "Meaning of Sin and Faith", Rawls attacked Pelagianism because it "would render the Cross of Christ to no effect". Rawls graduated from Princeton in 1943 with a Bachelor of Arts, summa cum laude.